[NUI] Add dispose checking in just a few methods of Timer class (#1339)

diff --git a/src/Tizen.NUI/src/public/Timer.cs b/src/Tizen.NUI/src/public/Timer.cs
index 6d86a25..3338616 100755 (executable)
--- a/src/Tizen.NUI/src/public/Timer.cs
+++ b/src/Tizen.NUI/src/public/Timer.cs
@@ -202,6 +202,12 @@ namespace Tizen.NUI
                 }
             }
 
+            if (swigCPtr.Handle == global::System.IntPtr.Zero || disposed)
+            {
+                NUILog.Error("[ERR] already disposed! can not get this done! just return here! please make sure that the handle gets free when using explicit Dispose()! For example, timer.Dispose(); timer = null; this must be done!");
+                return;
+            }
+
             played = true;
             Interop.Timer.Timer_Start(swigCPtr);
 
@@ -227,6 +233,12 @@ namespace Tizen.NUI
                 }
             }
 
+            if (swigCPtr.Handle == global::System.IntPtr.Zero || disposed)
+            {
+                NUILog.Error("[ERR] already disposed! can not get this done! just return here! please make sure that the handle gets free when using explicit Dispose()! For example, timer.Dispose(); timer = null; this must be done!");
+                return;
+            }
+
             played = false;
             Interop.Timer.Timer_Stop(swigCPtr);
 
@@ -252,6 +264,12 @@ namespace Tizen.NUI
                 }
             }
 
+            if (swigCPtr.Handle == global::System.IntPtr.Zero || disposed)
+            {
+                NUILog.Error("[ERR] already disposed! can not get this done! just return here! please make sure that the handle gets free when using explicit Dispose()! For example, timer.Dispose(); timer = null; this must be done!");
+                return false;
+            }
+
             bool ret = Interop.Timer.Timer_IsRunning(swigCPtr);
             if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
             return ret;
@@ -271,6 +289,12 @@ namespace Tizen.NUI
         {
             NUILog.Debug($"(0x{swigCPtr.Handle:X})SetInterval({milliSec})");
 
+            if (swigCPtr.Handle == global::System.IntPtr.Zero || disposed)
+            {
+                NUILog.Error("[ERR] already disposed! can not get this done! just return here! please make sure that the handle gets free when using explicit Dispose()! For example, timer.Dispose(); timer = null; this must be done!");
+                return;
+            }
+
             played = true;
 
             Interop.Timer.Timer_SetInterval(swigCPtr, milliSec);
@@ -279,6 +303,12 @@ namespace Tizen.NUI
 
         internal uint GetInterval()
         {
+            if(swigCPtr.Handle == global::System.IntPtr.Zero || disposed)
+            {
+                NUILog.Error("[ERR] already disposed! can not get this done! just return here! please make sure that the handle gets free when using explicit Dispose()! For example, timer.Dispose(); timer = null; this must be done!");
+                return 0;
+            }
+
             uint ret = Interop.Timer.Timer_GetInterval(swigCPtr);
             if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
             return ret;